NAME

mount, umount − mount and unmount a Network File System (NFS)

SYNTAX

/etc/mount −t nfs [ −r −v −o options ] device directory

/etc/umount [ −v ] directory

DESCRIPTION

The mount command allows you to mount a file system or directory onto a directory. Once a file system or directory has been mounted, it is treated as a file system.

The argument device can have one of the following forms:

host:remote_name

remote_name@host

The remote_name is the name of a file system or subtree of a file system that has been exported by host.  The file directory must exist and must be a directory.  It becomes the name of the newly mounted file system. 

The umount command unmounts the remote file system that was previously mounted on the specified directory.

OPTIONS

−fFast unmount.  The −f option has no meaning for local file systems and directories.  However, for remote file system types (such as NFS), the −f option causes the client to unmount the remotely mounted file systems and directories without notifying the server.  This can avoid the delay of waiting for acknowledgment from a server that is down. 

−rIndicates that the file system is to be mounted read only. 

−vTells what did or did not happen.  (Verbose flag)

−o optionsSpecifies options as a sequence of comma-separated words from the list below.  The defaults are: rw,hard,intr,retry=10,000,timeo=11,retrans=4,port=NFS_PORT,pgthresh=64 Defaults for rsize and wsize are set by the kernel.  The NFS options are:

bgIf the first mount attempt fails, retry the mount in the background the number of times specified (the default is 10,000 times). 

hardRetry the NFS operation (not the mount) request until server responds.  The hard option applies after the mount has succeeded.

intrAllow hard mounted file system operations to be interrupted. 

nintrDisallow hard mounted file system operations to be interrupted. 

noexecBinaries cannot be executed from this file system. 

nosuidThe setuid and setgid programs may not be executed from this file system.

pgthresh=##
Set the paging threshold for this file system in kilobytes.

port=nSet server IP port number to n. 

retrans=nSet number of NFS operation retransmissions (not the mount) to n.  The retrans= option applies after the mount has succeeded.

retry=nSet number of mount failure retries to n.  The retry= option applies to the mount command, itself.

roread-only. 

rsize=nSet read buffer size to n bytes. 

rwRead/write. 

softReturn an error if the server does not respond to the NFS operation (not the mount) request.  The soft option applies after the mount has succeeded.

timeo=nSet NFS timeout to n tenths of a second. 

wsize=nSet write buffer size to n bytes. 

The bg option causes mount to run in the background if the server’s mountd daemon does not respond. The mount command attempts each request retry=n times before giving up.  Once the file system is mounted, each NFS request made in the kernel waits timeo=n tenths of a second for a response.  If no response arrives, the time-out is multiplied by 2 and the request is retransmitted.  When retrans=n retransmissions have been sent with no reply, a soft mounted file system returns an error on the request and a hard mounted file system retries the request. If a hard mounted file system was mounted with the intr option, an operation within that file system that is retrying (for example, the server is down) can be interrupted. File systems that are mounted rw (read-write) should use the hard option. The number of bytes in a read or write request can be set with the rsize and wsize options.

The option for umount is:

−v Tells what did or did not happen.  (Verbose flag)

EXAMPLES

The mount command invokes nfs_mount to do its work. A sample mount command is:

# mount −t nfs −o hard,pgthresh=100 server:/usr /usr

To mount the remote file system /usr/src onto the local directory /mnt with 1k transfer size, type:

# mount −t nfs −o soft,rsize=1024,wsize=1024 serv:/usr/src /mnt

To mount the remote directory /usr/src/code onto the local directory /usr/src, type:

# mount −t nfs serv:/usr/src/code /usr/src

To hard mount a remote file system called /usr/src onto the local directory /usr/src, type:

# mount −t nfs −o hard serv:/usr/src /usr/src

umount command invokes

RESTRICTIONS

If the directory on which a file system is to be mounted is a symbolic link, the file system is mounted on the directory to which the symbolic link refers, rather than being mounted on top of the symbolic link itself. 

The /etc/nfs_mount and /etc/nfs_umount commands should only be invoked by the mount and umount commands. Users (and superusers) should not invoke the nfs_mount and nfs_umount commands.

FILES

/etc/fstabFile system information file /etc/nfs_mount NFS-specific mount program /etc/nfs_umount NFS-specific unmount program

SEE ALSO

getmnt(2), mount(2), fstab(5), exports(5nfs), mount(8), umount(8), mountd(8nfs)